Cost per apartment of supportive housing in Seattle and King County, 2021-2025

What this dataset measures

Permanent supportive housing gives formerly homeless people an apartment with on-site services. The Washington State Department of Commerce publishes every application to its Housing Trust Fund with the project's estimated total residential development cost and its count of supportive housing units, and its annual cost data reports list final costs for finished buildings. These are the only public, project-by-project totals we found; the City of Seattle's reports give only the City's share. We kept every Seattle new-construction application from 2021 to 2025 in which all apartments are supportive housing.

Geography

Seattle, Washington, United States, King County, Washington, United States

Unit of observation

One building (project), with its cost per apartment

Update cadence

Yearly, when Commerce posts a new application list or cost report

Curator

FactHub Research Team

Curated data tables

These related tables form this versioned dataset release. Each table has its own downloadable file and field definitions.

Supportive housing buildings and their cost per apartment

Planned and finished supportive housing buildings in Seattle and nearby cities, and buildings King County bought for its Health Through Housing program.

Unit of observation: One building

View this table

psh_projects.csv text/csv · 5.2 KB (5,355 bytes)

16 field definitions

Field	Type	Meaning	Units	Value type
project_id	string	Our identifier for the row	—	derived
name_as_listed	string	Project name as the source lists it	—	observed
sponsor	string	Nonprofit developer or service provider	—	observed
city	string	City where the building is	—	observed
category	string	planned_new (Seattle, all units supportive, new construction), planned_new_superseded (an earlier estimate for a project that re-applied), planned_new_suburb, completed_new (final cost, Seattle), completed_new_suburb, county_purchase (bought by King County)	—	derived
year	integer	Application year for planned buildings; report year for finished buildings and county purchases	—	observed
units	integer	Total low-income units (planned) or total units (finished)	apartments	observed
total_cost_usd	number	Total residential development cost (estimated) for planned buildings	U.S. dollars	estimated
acquisition_per_unit_usd	number	County purchase cost per unit, life to date	U.S. dollars per unit	observed
rehab_per_unit_usd	number	County rehabilitation cost per unit, life to date	U.S. dollars per unit	observed
cost_per_apartment_usd	number	Cost per apartment	U.S. dollars per apartment	derived
cost_per_residential_sqft_usd	number	Final cost per residential square foot (includes common areas and parking)	U.S. dollars per square foot	observed
value_kind	string	estimated (application) or observed (final or recorded cost)	—	derived
status	string	County building status at December 2024	—	observed
source_id	string	Source of the row's figures	—	observed
note	string	Details and caveats for the row	—	observed

Seattle affordable buildings with no supportive housing, 2023 applications

New-construction affordable buildings in Seattle with no supportive housing units that applied to the Housing Trust Fund in 2023.

Unit of observation: One building

View this table

seattle_affordable_2023_applications.csv text/csv · 734 bytes

4 field definitions

Field	Type	Meaning	Units	Value type
project	string	Project name as listed	—	observed
units	integer	Total low-income housing units	apartments	observed
residential_development_cost_usd	number	Total residential development cost (estimate)	U.S. dollars	estimated
cost_per_apartment_usd	number	Cost per apartment	U.S. dollars per apartment	derived

Comparison figures

A typical new apartment's cost per unit in Seattle, King County program averages and the state's King County median.

Unit of observation: One comparison figure

View this table

benchmarks.csv text/csv · 842 bytes

6 field definitions

Field	Type	Meaning	Units	Value type
benchmark_id	string	Identifier	—	derived
description	string	What the figure measures	—	observed
value_usd	number	The figure	U.S. dollars (see unit)	observed
unit	string	Unit of the figure	—	observed
source_id	string	Source	—	observed
note	string	Notes	—	observed

Supporting files

Source snapshots, manifests, quality reports, documentation, and other materials used to produce or review this release.

• build.py Transformation manifest · text/x-python · 10.2 KB (10,486 bytes)

  Python script that writes the three tables from the transcribed figures and computes every median.

Saved analyses

Sources

1. Washington State Department of Commerce, list of 2021 Housing Trust Fund and Cottage applications Estimated cost and supportive housing units for DESC Greenlake and DESC Woodland (2021)

   Retrieved November 11, 2026. Public record (Washington State government). Figures only; the source file is linked, not hosted

   Reliability: Government. Commerce runs the state Housing Trust Fund and posts every application it receives. Costs are the applicants' own estimates.

2. Washington State Department of Commerce, list of 2022 Housing Trust Fund applications Estimated cost and supportive housing units for DESC 15th Avenue and Plymouth's Kenmore building (2022)

   Retrieved November 11, 2026. Public record (Washington State government). Figures only; the source file is linked, not hosted

   Reliability: Government. Posted by the agency that runs the fund. Costs are the applicants' own estimates.

3. Washington State Department of Commerce, list of 2023 Housing Trust Fund applications Estimated cost for DESC Lake City and DESC Woodland, and for 15 Seattle affordable buildings with no supportive housing (2023)

   Retrieved November 11, 2026. Public record (Washington State government). Figures only; the source file is linked, not hosted

   Reliability: Government. Posted by the agency that runs the fund. The list also gives each project's activity type, such as new construction (NC).

4. Washington State Department of Commerce, 2024 Traditional Housing Trust Fund Applications Received (NOFA #MHU-2024-02), updated 11/08/2024 Anticipated cost and supportive housing units for DESC Belmont, Plymouth's Norkirk and Redmond buildings (2024)

   Retrieved November 11, 2026. Public record (Washington State government). Figures only; the source file is linked, not hosted

   Reliability: Government. Posted by the agency that runs the fund; column 'Anticipated Total Residential Development Costs'.

5. Washington State Department of Commerce, list of 2025 Housing Trust Fund applications Anticipated cost and supportive housing units for Plymouth's Whittier Housing (2025)

   Retrieved November 11, 2026. Public record (Washington State government). Figures only; the source file is linked, not hosted

   Reliability: Government. Posted by the agency that runs the fund. Costs are the applicants' own estimates.

6. Washington State Department of Commerce, 2022 Housing Trust Fund Affordable Housing Cost Data Report Final cost per unit for DESC 22nd Avenue PSH (Seattle) and Kent Permanent Supportive Housing; definition of total residential project cost

   Retrieved November 11, 2026. Public record (Washington State government). Figures only; the source file is linked, not hosted

   Reliability: Government. Required by state law (RCW 43.185A.190). Built from final cost certifications that funded projects submit to Commerce.

7. Washington State Department of Commerce, 2023 Annual Affordable Housing Cost Data Report Final cost per unit and per square foot for four Seattle supportive housing buildings; King County median for all state-funded new buildings

   Retrieved November 11, 2026. Public record (Washington State government). Figures only; the source file is linked, not hosted

   Reliability: Government. Covers projects that submitted final cost data from July 2022 to June 2023. Commerce notes that only 26% of awardees had submitted cost certifications.

8. King County, 2024 Health Through Housing Annual Report (Attachment A to Motion 16910) Per-unit acquisition and rehabilitation cost for each building the county bought, each building's city and status, average capital and operating cost

   Retrieved November 11, 2026. Public record (King County government). Figures only; the source file is linked, not hosted

   Reliability: Government. Has a stake in this finding. Written by the county department that runs the program, for the County Council. Costs are the county's own accounting, not audited figures.

9. BAE Urban Economics for the Portland Housing Bureau, Residential Development Cost Study Summary (January 30, 2024) Estimated full cost per unit of a typical new six-story apartment building in Seattle

   Retrieved November 11, 2026. Public record (City of Portland). Figures only; the source file is linked, not hosted

   Reliability: Other. Consultant study paid for by the City of Portland. Seattle costs come from spring 2023 interviews with developers and contractors plus public and private data, for one typical building design.

License: FactHub's selection, cleaning and combined tables are licensed under CC BY 4.0. Source data keeps the terms listed above (terms).

Limitations and reproducibility

Reproducible from public sources: Each planned building's cost per apartment is its 'Total Residential Development Cost' (2021-2023 lists) or 'Anticipated Total Residential Development Costs' (2024-2025 lists) divided by its total low-income units, as printed in Commerce's application list for that year. Finished buildings' cost per unit is printed in the cost data reports. County purchase costs are the per-unit acquisition and rehabilitation figures in Figure 20 of King County's 2024 Health Through Housing report, added together. build.py recomputes every table and median from these transcribed figures.

• Costs for planned buildings are the sponsors' estimates when they applied for state money. Final costs can differ; DESC Woodland's estimate rose 38% between its 2021 and 2023 applications.
• Only buildings that applied to the state Housing Trust Fund appear. Seattle supportive housing financed without an application to that fund is missed.
• Four Seattle buildings planned in 2023-2025 is a small sample, so one project can move the median.
• Cost per apartment does not adjust for size. Supportive housing apartments are mostly studios; the typical new apartment benchmark building averages about 700 square feet per unit including common space.
• Costs include land, construction, fees, financing and reserves for the residential part of each building, including shared service space; commercial space is excluded. They are nominal dollars, not adjusted for inflation.
• King County's purchase costs are life-to-date through 2024. Several bought buildings were still being renovated or not yet open, so their final cost per unit will be higher. The report does not say whether it divides by the units at purchase or the units after conversion.
• Cost per apartment is a one-time building cost. It is not the cost per resident, and it leaves out yearly operating and service costs.